I managed to restore functionality to Radeon Settings and Steam, and Windows 7 now boots without error messages.
I don't use System Restore, because a) it never works and b) a huge waste of time and storage.
sfc /scannow seems fairly effective at replacing fucked system files.
I did dl an official Win10 installer iso, waiting for an opportune time to deal with the potentially system-nuking fallout
I looked into the running FC5 on Wine thing in more detail TL;DR this trick may be even more fraught than essaying a Win7/Win10/Linux multiboot. Not had good experiences with Wine (see System Restore ^^^), allowing how it's matured since I last fucked with it. Since this is my production system ...
"Kentucky man seeking parole says he still hears voices that led to school shooting"